1. Technical Field
The present invention relates to a duplex image forming apparatus, and more particularly, to a paper guide device which can easily eliminate a paper jam on a paper feed path for duplexing printing.
2. Related Art
A printer is a device that is able to print information onto a sheet of paper. Typically, a printer includes a set of rollers able to feed a sheet of paper along a path while the information is being printed onto the sheet of paper. Sometimes a jam occurs in a printer when a sheet of paper adheres improperly to a roller or when a sheet of paper is fed in an incorrect manner.
A simplex printing process is a printing process which records information onto one side of a sheet of paper. A duplex printing process is a printing process which records information onto both sides of a sheet of paper. A duplex printer is a printer that is able to print information onto both sides of a sheet of paper. Jams sometimes occur more frequently during duplex printing than during simplex printing. This increase in the occurrence of jams during duplex printing can often be attributed to the increased complexity involved during duplex printing.
Some duplex printers include a set of rollers able to rotate in a clockwise direction and in a counterclockwise direction. Thus, while information is printed onto a first side of a sheet of paper, a duplex printer's rollers may be rotating in a first direction to feed the sheet of paper along a first path. Then, after the information has been printed onto the first side of the sheet of paper, the duplex printer's rollers may be required to rotate in a second direction in order to feed the sheet of paper along a second path so that data can be printed onto the second side of the sheet of paper.
I have found that paper jams during any type of printing process, including a duplex printing process, can be extremely inconvenient. Efforts have been made to reduce the occurrence of paper jams.
Exemplars of recent efforts in the art include U.S. Pat. No. 5,258,818 for Photocopier with Duplex Tray Save after Jam issued to Sundquist et al., U.S. Pat. No. 5,081,490 for Method of Controlling Image Forming Apparatus When a Jam Occurs in the Original Feeder issued to Wakao, U.S. Pat. No. 5,034,771 for Copier Having Superimposed and Duplex Copying Capabilities and Capable of Discriminating False Paper Jam and Real Paper Jam issued to Makita, U.S. Pat. No. 5,030,991 for Jam Detection and Clearance System for Duplex Copiers issued to Zaitsu et al., U.S. Pat. No. 4,878,087 for Image Forming Apparatus with Jam Removal Mechanism issued to Sakai et al., and U.S. Pat. No. 4,090,787 for Automatic Copier Mode Controls issued to Hubbard et al.
While these recent efforts provide advantages, I note that they fail to adequately address how a paper guide can conveniently and efficiently eliminate a paper jam for duplex printing.